Is melatonin a helpful sleep aid — and what should I know about melatonin side effects?

The hormone melatonin plays a role in your natural sleep-wake cycle. Natural levels of melatonin in the blood are highest at night. Some research suggests that melatonin supplements taken at the right time might be helpful in treating jet lag or other sleep disorders that involve poor alignment of your natural biological clock with the night-day pattern around you. Melatonin might also reduce the time it takes to fall asleep — although this effect is typically mild.

Melatonin might be more effective for other types of sleep issues, such as delayed sleep disorder or other sleep disorders affecting circadian rhythm.

The most common melatonin side effects include:

Daytime sleepiness

Headaches

Dizziness

Other, less common melatonin side effects might include abdominal discomfort, mild anxiety, irritability, confusion and short-lasting feelings of depression.

In addition, melatonin supplements can interact with various medications, including:

Blood-thinning medications (anticoagulants)

Medications that suppress the immune system (immunosuppressants)

Diabetes medications

Birth control pills

If you're considering taking melatonin supplements, check with your doctor first — especially if you have any health conditions. He or she can help you determine the correct dose, which depends on the intended use.

If you take melatonin, choose commercial supplements produced in a lab. Melatonin supplements made from animal sources might contain contaminants. Avoid activities that require alertness — such as driving or operating heavy machinery — for four to five hours after taking melatonin. Also, melatonin is generally recommended only for short-term use — up to two months. Some research indicates that longer term use might be appropriate in certain cases, however.

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